# Kconfig - miscellany configuration options # # Copyright (c) 2014-2015 Wind River Systems, Inc. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. # menu "Compile and Link Features" menu "Linker Options" config TEXT_SECTION_OFFSET hex "TEXT section offset" default 0 help This sets and offset before the text section and allows booting images with custom headers that are inserted at the beginning of the image. config HAVE_CUSTOM_LINKER_SCRIPT prompt "Custom linker scripts provided" def_bool n help Set this option if you have a custom linker script which needed to be define in CUSTOM_LINKER_SCRIPT. config CUSTOM_LINKER_SCRIPT string "Path to custom linker script" default "" depends on HAVE_CUSTOM_LINKER_SCRIPT help Path to the linker script to be used instead of the one define by the board. The linker script must be based on a version provided by Zephyr since the kernel can expect a certain layout/certain regions. This is useful when an application needs to add sections into the linker script and avoid having to change the script provided by Zephyr. config CUSTOM_RODATA_LD bool "Include custom-rodata.ld" default n help Include a customized linker script fragment for inserting additional data and linker directives into the rodata section. config CUSTOM_RWDATA_LD bool "Include custom-rwdata.ld" default n help Include a customized linker script fragment for inserting additional data and linker directives into the data section. config CUSTOM_SECTIONS_LD bool "Include custom-sections.ld" default n help Include a customized linker script fragment for inserting additional arbitrary sections. config LINK_WHOLE_ARCHIVE bool "Allow linking with --whole-archive" default n help This options allows linking external libraries with the --whole-archive option to keep all symbols. endmenu menu "Compiler Options" config CROSS_COMPILE string "Cross-compiler tool prefix" help Same as running 'make CROSS_COMPILE=prefix-' but stored for default make runs in this kernel build directory. You don't need to set this unless you want the configured kernel build directory to select the cross-compiler automatically. config COMPILER_OPT string prompt "Custom compiler options" default "" help This option is a free-form string that is passed to the compiler when building all parts of a project (i.e. kernel). The compiler options specified by this string supplement the pre-defined set of compiler supplied by the build system, and can be used to change compiler optimization, warning and error messages, and so on. config TOOLCHAIN_VARIANT string "Cross-compiler variant name" help For optimized compilers with reduced features, specify the name of the variant. endmenu config CPLUSPLUS bool "Enable C++ support for the application" default n help This option enables the use of applications built with C++. config GDB_INFO bool prompt "Task-aware debugging with GDB" default n help This option enables the kernel to collect additional information during interrupts, exceptions, and context switches. This information is required for task-aware debugging with GDB. config KERNEL_BIN_NAME string "The kernel binary name" default "zephyr" help This option sets the name of the generated kernel binary. endmenu menu "Debugging Options" config DEBUG bool "Build kernel with debugging enabled" default n help Build a kernel suitable for debugging. Right now, this option only disables optimization, more debugging variants can be selected from here to allow more debugging. config STACK_USAGE bool "Generate stack usage information" default n help Generate an extra file that specifies the maximum amount of stack used, on a per-function basis. config PRINTK bool prompt "Send printk() to console" depends on CONSOLE_HAS_DRIVER default y help This option directs printk() debugging output to the supported console device, rather than suppressing the generation of printk() output entirely. Output is sent immediately, without any mutual exclusion or buffering. config STDOUT_CONSOLE bool prompt "Send stdout to console" depends on CONSOLE_HAS_DRIVER default n help This option directs standard output (e.g. printf) to the console device, rather than suppressing it entirely. config EARLY_CONSOLE bool prompt "Send stdout at the earliest stage possible" default n help This option will enable stdout as early as possible, for debugging purpose. For instance, in case of STDOUT_CONSOLE being set it will initialize its driver earlier than normal, in order to get the stdout sent through the console at the earliest stage possible. config ASSERT bool prompt "Enable __ASSERT() macro" default n help This enables the __ASSERT() macro in the kernel code. If an assertion fails, the calling thread is put on an infinite tight loop. Since enabling this adds a significant footprint, it should only be enabled in a non-production system. config ASSERT_LEVEL int prompt "__ASSERT() level" default 2 range 0 2 depends on ASSERT help This option specifies the assertion level used by the __ASSERT() macro. It can be set to one of three possible values: Level 0: off Level 1: on + warning in every file that includes __assert.h Level 2: on + no warning config DEBUG_TRACING_KERNEL_OBJECTS bool "Kernel object tracing (deprecated)" select OBJECT_TRACING default n help For backward compatibility only config OBJECT_TRACING bool prompt "Kernel object tracing" default n help This option enable the feature for tracing kernel objects. This option is for debug purposes and increases the memory footprint of the kernel. config OMIT_FRAME_POINTER bool prompt "Omit frame pointer" default n help Prevent the compiler from putting the stack frame pointer into a register. Saves a few instructions in function prologues/epilogues and frees up a register for general-purpose use, which can provide good performance improvements on register-constrained architectures like x86. Omitting frame pointers impedes debugging as local variables are harder to locate and it is much more difficult to produce a stack trace. Recommended only for production builds which do not need to be debugged. endmenu menu "System Monitoring Options" config PERFORMANCE_METRICS bool prompt "Enable performance metrics [EXPERIMENTAL]" default n help Enable Performance Metrics. config BOOT_TIME_MEASUREMENT bool prompt "Boot time measurements [EXPERIMENTAL]" default n depends on PERFORMANCE_METRICS help This option enables the recording of timestamps during system start up. The global variable __start_tsc records the time kernel begins executing, while __main_tsc records when main() begins executing, and __idle_tsc records when the CPU becomes idle. All values are recorded in terms of CPU clock cycles since system reset. config CPU_CLOCK_FREQ_MHZ int prompt "CPU CLock Frequency in MHz" default 20 depends on BOOT_TIME_MEASUREMENT help This option specifies the CPU Clock Frequency in MHz in order to convert Intel RDTSC timestamp to microseconds. endmenu menu "Boot Options" config IS_BOOTLOADER bool "Act as a bootloader" default n depends on XIP depends on ARM help This option indicates that Zephyr will act as a bootloader to execute a separate Zephyr image payload. config BOOTLOADER_SRAM_SIZE int "SRAM reserved for when Zephyr acts as a bootloader" default 16 depends on !XIP || IS_BOOTLOADER depends on ARM help This option specifies the amount of SRAM (measure in kB) reserved for when Zephyr is to act as a bootloader. config BOOTLOADER_KEXEC bool prompt "Boot using Linux kexec() system call" depends on X86 default n help This option signifies that Linux boots the kernel using kexec system call and utility. This method is used to boot the kernel over the network. config BOOTLOADER_UNKNOWN bool prompt "Generic boot loader support" default n depends on X86 help This option signifies that the target has a generic bootloader or that it supports multiple ways of booting and it isn't clear at build time which method is to be used. When this option is enabled the board may have to do extra work to ensure a proper startup. config BOOTLOADER_CONTEXT_RESTORE bool prompt "Boot loader has context restore support" default y depends on SYS_POWER_DEEP_SLEEP && BOOTLOADER_CONTEXT_RESTORE_SUPPORTED help This option signifies that the target has a bootloader that restores CPU context upon resuming from deep sleep power state. config REBOOT bool "Reboot functionality" default n select SYSTEM_CLOCK_DISABLE help Enable the sys_reboot() API. Enabling this can drag in other subsystems needed to perform a "safe" reboot (e.g. SYSTEM_CLOCK_DISABLE, to stop the system clock before issuing a reset). endmenu